Fix set splash icon in webApk update request

The created SkBitmap was not set to |splash_icon| correctly and it will
always be null.
Add a "splash_icon = " to fix that.

Bug: None
Change-Id: Id229c1658612b092cbaf5452dc9a7a250207f567
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2163075
Commit-Queue: Ella Ge <eirage@chromium.org>
Reviewed-by: Peter Kotwicz <pkotwicz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#762079}

chrome/browser/android/webapk/webapk_update_manager.cc

@@ -159,6 +159,7 @@ static void JNI_WebApkUpdateManager_StoreWebApkUpdateRequestToFile(
   SkBitmap splash_icon;
   if (!java_splash_icon_bitmap.is_null()) {
     gfx::JavaBitmap java_splash_icon_bitmap_lock(java_splash_icon_bitmap);
+    splash_icon =
         gfx::CreateSkBitmapFromJavaBitmap(java_splash_icon_bitmap_lock);
     splash_icon.setImmutable();
   }